re PR tree-optimization/16383 (internal compiler error: in generate_element_copy, at tree-sra.c:1466)

        PR tree-opt/16383
        * tree-ssa-ccp.c (fold_stmt_r): Split out...
        * tree.c (fields_compatible_p, find_compatible_field): ... new.
        * tree.h (fields_compatible_p, find_compatible_field): Declare.
        * tree-sra.c (sra_hash_tree): Hash fields by offset.
        (sra_elt_eq): Use fields_compatible_p.
        (generate_one_element_ref): Use find_compatible_field.

From-SVN: r84524